Various commercial and industrial properties of polymeric materials can be developed by the way of purposeful synthesis. For example, there are polymeric materials of extremely developed intrinsic microporosity. In attempts to further develop membrane properties (permeability and selectivity), the researchers artificially increase the pore sizes by various external influences, such as plastification by saturation of polymers with gases, sometimes in supercritical state, filling of a polymer with some non-organic components (zeolites). Sometimes, porosity of the composition appears to become higher than that of the components. This porosity, in difference with intrinsic one, can be called externally affected. The reason of these phenomena is not always clear, and in order to get some ideas in this field we suggest an experimental study using a combination of the two genetically interconnected (by spur processes) methods: positron annihilation lifetime spectroscopy and thermostimulated luminescence. This paper summarizes recently published and completely new results of the authors in order to illustrate the benefits of this experimental approach.